package com.ybg.base.util;
/**
 * java版的escape和unescape方法解析类.
 * 
 * @author https://gitee.com/YYDeament/88ybg
 * 
 * 
 * @version 1.0
 */
public class EncodingUtil {
    
    /**
     * 对字符串进行编码.
     * 
     * @param source
     * @return
     */
    public static String escape(String source){
        int i;
        char j;
        StringBuffer tmp = new StringBuffer();
        tmp.ensureCapacity(source.length() * 6);
        for (i = 0; i < source.length(); i++) {
            j = source.charAt(i);
            if (Character.isDigit(j) || Character.isLowerCase(j) || Character.isUpperCase(j)) {
                tmp.append(j);
            }
            else if (j < 256) {
                tmp.append("%");
                if (j < 16) {
                    tmp.append("0");
                }
                tmp.append(Integer.toString(j, 16));
            }
            else {
                tmp.append("%u");
                tmp.append(Integer.toString(j, 16));
            }
        }
        return tmp.toString();
    }
    
    /**
     * 对字符串进行解码.
     * 
     * @param source
     * @return
     */
    public static String unescape(String source){
        StringBuffer tmp = new StringBuffer();
        tmp.ensureCapacity(source.length());
        int lastPos = 0, pos = 0;
        char ch;
        while (lastPos < source.length()) {
            pos = source.indexOf("%", lastPos);
            if (pos == lastPos) {
                if (source.charAt(pos + 1) == 'u') {
                    ch = (char) Integer.parseInt(source.substring(pos + 2, pos + 6), 16);
                    tmp.append(ch);
                    lastPos = pos + 6;
                }
                else {
                    ch = (char) Integer.parseInt(source.substring(pos + 1, pos + 3), 16);
                    tmp.append(ch);
                    lastPos = pos + 3;
                }
            }
            else {
                if (pos == -1) {
                    tmp.append(source.substring(lastPos));
                    lastPos = source.length();
                }
                else {
                    tmp.append(source.substring(lastPos, pos));
                    lastPos = pos;
                }
            }
        }
        return tmp.toString();
    }
    
    private EncodingUtil(){
    }
}
